The BBC is reporting that a new study suggests that our mental abilities start to dwindle at 27 after peaking at 22, and 27 could be seen as the 'start of old age.' The seven-year study, by Professor Timothy Salthouse of the University of Virginia, looked at 2,000 healthy people aged 18-60, and used a number of mental agility tests already used to spot signs of dementia. 'The first age at which there was any marked decline was at 27 in tests of brain speed, reasoning and visual puzzle-solving ability. Things like memory stayed intact until the age of 37, on average, while abilities based on accumulated knowledge, such as performance on tests of vocabulary or general information, increased until the age of 60.